An image forming apparatus performing development using light toner of a first color and dark toner of the first color includes a control unit configured to control tone in order to set gradation characteristics of an image developed with the light toner; a determination unit configured to determine whether the gradation characteristics of the light toner image are in a desirable state as a result of the tone control by the control unit; and a shift unit configured to shift an area where mixture of the light toner with the dark toner is started, the area corresponding to the desirable state, responsive to the determination unit determining that the gradation characteristics of the light toner image are not in the desirable state.